Answer
$\dfrac{256}{625}$
Work Step by Step
(i) $a^{-m} = \dfrac{1}{a^m}, a\ne0$
(ii) $\left(\dfrac{a}{b}\right)^m=\dfrac{a^m}{b^m}, b \ne0$
Use the rules above to obtain:
$=\dfrac{1}{(\frac{5}{4})^4}
\\=\dfrac{1}{\frac{5^4}{4^4}}
\\=1 \cdot \dfrac{4^4}{5^4}
\\=\dfrac{4^4}{5^4}
\\=\dfrac{256}{625}$
